namespace InnovEnergy.API.DataModel;

public static class FolderExtensions
{
    public static IEnumerable<Path> DescendantUserParents(this Folder folder)
    {
        foreach (var path in folder.GetDescendantFolders())
        {
            yield return path;

            var f = path.Folder()!;

            foreach (var installation in f.Installations)
                yield return new Path(path, installation);
        }
    }

    public static IEnumerable<Path> DescendantFolders(this Folder folder) => folder.GetDescendantFolders();

    public static IEnumerable<Path> DescendantInstallations(this Folder folder)
    {
        return from path in folder.DescendantFolders()
            let f = path.Element as Folder
            from installation in f.Installations
            select new Path(path, installation);
    }


    public static IEnumerable<Path> DescendantUsers(this Folder folder)
    {
        IEnumerable<User> GetUsers(Folder f) => f
            .Installations
            .SelectMany(i => i.Users)
            .Concat(f.Users);

        return from path in folder.DescendantFolders()
            from user in GetUsers(path.Folder())
            select new Path(path, user);
    }




    public static Path? FindDescendantUser(this Folder folder, String userName)
    {
        return folder
            .DescendantUsers()
            .FirstOrDefault(f => f.Element.Name == userName);
    }


    private static IEnumerable<Path> GetDescendantFolders(this Folder folder, Path? parent = null)
    {
        var path = new Path(parent, folder);

        yield return path;

        var descendantFolders = from f in folder.Folders
            from descendant in f.GetDescendantFolders(path)
            select descendant;

        foreach (var descendant in descendantFolders)
            yield return descendant;
    }

    public static Boolean Remove(this Folder folder, Installation installation)
    {
        return folder.Installations.Remove(installation);
    }

    public static void Add(this Folder folder, Installation installation)
    {
        folder.Installations.Add(installation);
    }

    public static Boolean Remove(this Folder folder, Folder child)
    {
        return folder.Folders.Remove(child);
    }

    public static void Add(this Folder folder, Folder child)
    {
        folder.Folders.Add(child);
    }


    public static VrmInstallation GetOrCreateVrmInstallation(this Folder folder, String uniqueId)
    {
        var vrmInstallation = folder
            .Installations
            .OfType<VrmInstallation>()
            .FirstOrDefault(i => i.UniqueId == uniqueId);

        if (vrmInstallation is not null)
            return vrmInstallation;   // installation exist, return it

        vrmInstallation = new VrmInstallation();
        folder.Installations.Add(vrmInstallation);

        return vrmInstallation;
    }

    public static Boolean IsEmpty(this Folder folder) => !folder.Folders.Any() && !folder.Installations.Any();

}